This invention relates to a motorized expander for one, two or more cloth widths, usable on all types of fabric.
Expanders are commonly used industrially, being devices inserted in the manufacturing line for fabrics in order to stretch them in the direction of their width, so as to prevent their shrinkage or the curling of the selvedges.
Known expanders are of the rotating curved type, the double opposite fixed spiral type or the motorized spiral type. These expanders have common disadvantages, the most important of which is represented by the complicated operations which have to be carried out on the expander when a fabric of a width different from the width of the previously worked fabric is to be stretched. For example, in the case of rotating curved expanders or double opposite fixed spiral expanders, in which differently wide fabrics are worked on different surfaces of the device, said operations involve overturning of the respective device so as to introduce the appropriate surface into the fabric path (in fixed expanders) or changing the cloth threading of a processing line (in rotating curved expanders). Both these operations create downtimes in production, with obvious repercussions on the economy of the process.
A further disadvantage encountered in known types of expander is their limited applicability to certain types of textile materials. For example, opposite fixed spiral expanders are suitable for processing woven fabrics, but cannot be effectively applied to knitted fabrics.
A further disadvantage in the case of rotating curved expanders is their large overall dimensions.